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Re: [cffi-devel] Converting foreign structures with CFFI generic functions
by Luís Oliveira 10 Sep '11

10 Sep '11

On Fri, Sep 9, 2011 at 3:47 PM, Liam Healy <lnp(a)healy.washington.dc.us> wrote: > If you could that would be great, I think you could do that much > quicker than I could. If you make your new class in the fsbv branch, > I will pull from there and continue the development of structure > definition and conversion in src/structures.lisp. I've created a pull request at github for more code-centered discussion, mostly out of curiosity to see how that works. <https://github.com/cffi/cffi/pull/2> -- Luís Oliveira http://r42.eu/~luis/

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[cffi-devel] Converting foreign structures with CFFI generic functions
by Liam Healy 09 Sep '11

09 Sep '11

I'm looking for some clarification of the design and intent of some CFFI definitions. As has been mentioned in another thread, I am working on incorporating my system Foreign Structures By Value, FSBV, into CFFI. As a first step toward that integration, I have been looking at conversion of objects from CL to foreign and vice versa, with the idea of unifying the approach to include foreign structures. My goal is to be as consistent with the existing CFFI design as I can be. My understanding is that CFFI's conversion design is expressed in the generic functions translate-to-foreign, translate-from-foreign, and free-translated-object, to which applications may add methods, and the functions convert-to-foreign and convert-from-foreign to permit the user to make a conversion manually. At present there are no definitions to convert foreign structures, and I'd like to add that. I think my approach should be to add methods to translate-*-foreign and free-translated-object, or have defcstruct add the methods when it is expanded. My thought now is that I should define methods for translate-*-foreign and free-translated-object dispatching on the foreign-struct-type class. The body will call the same method with the structure name, and applications can define methods eql-specialized on the name. Does this sound like it will work correctly with CFFI as it exists now, so that I can then introduce the libffi interface for the calls to foreign functions? Thanks, Liam

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[cffi-devel] Passing address of pointer
by Frank Goenninger 07 Sep '11

07 Sep '11

Hi all, I have a C struct as follows: (defcstruct MyPrivateData (notification io_object_t) (deviceInterface :pointer) ;; void pointer (deviceName CFStringRef) (locationID UInt32)) of which the deviceInterface slot is the one I'm interested in. I need to pass the address of the deviceInterface pointer to a function that sets the pointer to valid device interface struct. So... In the sample code from Apple the C function is called like this: typedef struct MyPrivateData { io_object_t notification; IOUSBDeviceInterface **deviceInterface; CFStringRef deviceName; UInt32 locationID; } MyPrivateData; IOCFPlugInInterface **plugInInterface = NULL; SInt32 score; HRESULT res; res = (*plugInInterface)->QueryInterface( plugInInterface, CFUUIDGetUUIDBytes( kIOUSBDeviceInterfaceID ), (LPVOID*) &privateDataRef->deviceInterface ); How would I translate this call into a valid CFFI equivalent ? I have so far: (let ((query-interface-ptr (foreign-slot-value plugInInterface 'IOCFPlugInInterface 'ccag.osx.iokit::QueryInterface))) (format *debug-io* "~%DEVICE-ADDED: query-interface-ptr = ~s." query-interface-ptr) (setq res (foreign-funcall-pointer query-interface-ptr () :pointer plugInInterface CFUUIDBytes (cf-uuid-get-uuid-bytes kIOUSBDeviceInterfaceID) :pointer (foreign-slot-pointer privateDataRef 'MyPrivateData 'deviceInterface))) (format *debug-io* "~%DEVICE-ADDED: deviceInterface = ~s." (foreign-slot-value privateDataRef 'MyPrivateData 'deviceInterface)) ... This code "crashes" with signal 100 as reported by AllegroCL in the call to foreign-funcall-pointer ... Any hints or advice really appreciated! TIA! Best wishes Frank

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[cffi-devel] reloading foreign libraries
by parisnight＠softhome.net 19 Jun '11

19 Jun '11

Hi, I'd like to be able to edit a foreign file and reload it into my lisp image without having to restart lisp. I am running clisp 2.47 with cffi 10.6 under XP (not my choice). I can close-foreign-function with a T result. However, the dll seems to still be locked from being overwritten by the compiler. In addition, when I try to load a slightly modified dll with a different filename, the load-foreign-library fails with: Unable to load foreign library (LIBRARY-15386). FFI:OPEN-FOREIGN-LIBRARY: Cannot open library "c:/v/site/jpars/Project3" [Condition of type LOAD-FOREIGN-LIBRARY-ERROR] Anybody know how to reload a C library on XP without having to quit the lisp interpreter? Thanks, Bob

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[cffi-devel] foreign-free not freeing memory not allocated by CFFI
by Luke Crook 23 May '11

23 May '11

I received a report of an error when a function is called from lispbuilder-sdl-mixer on the Mac in both SBCL and CCL. http://pastebin.com/NmLX1Hgg I think the problem is that CFFI does not allow memory to be freed if that memory has not also been allocated using CFFI. In my code below, a new 'sdl-version' struct is returned by (sdl-mixer-cffi::linked-version). The error seems to occur when I try to free the struct at the end of the function using foreign-free. (defun linked-version () "Returns the version number of the SDL_mixer dynamic library in use as #\(`MAJOR` `MINOR` `PATCH`\)." (let ((sdl-version (sdl-mixer-cffi::linked-version)) (version nil)) (cffi:with-foreign-slots ((sdl-cffi::major sdl-cffi::minor sdl-cffi::patch) sdl-version sdl-cffi::sdl-version) (setf version (vector sdl-cffi::major sdl-cffi::minor sdl-cffi::patch))) (cffi:foreign-free sdl-version) version)) Can I get around this somehow? -Luke

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[cffi-devel] HDF5 bindings
by Daniel Herring 20 May '11

20 May '11

Hi all, I've made good progress on binding the HDF5 file format library. HDF5 is an efficient, self-describing, extensible, binary file format that is popular in scientific computing, underlies NetCDF, is used by petabytes of data, is supported by tools like Matlab, ... http://www.hdfgroup.org/HDF5/whatishdf5.html My bindings are not quite ready for general consumption by the average CL user, but they should be quite usable by a CFFI programmer. The sources are here: https://gitorious.org/dh-misc/hdf5 Please read the README.txt first. As always, help would be appreciated, and the usual disclaimers of "this software may munge your data" apply. Later, Daniel

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Re: [cffi-devel] Reports of CFFI's orphanage greatly exhagerated (sic)
by Luís Oliveira 16 May '11

16 May '11

In other news, I don't know how to to spell "exaggerated"... -- Luís Oliveira http://r42.eu/~luis/

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[cffi-devel] Reports of CFFI's orphanage greatly exhagerated
by Luís Oliveira 16 May '11

16 May '11

Hello, A couple of people sent me emails about <http://netzhansa.blogspot.com/2011/05/orphaned-projects-on-common-lispnet.h…> which lists CFFI as an orphaned project. Turns out James Bielman's domain has expired, and now I get to regularly delete mailman moderation notices. Yay. -- Luís Oliveira http://r42.eu/~luis/

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[cffi-devel] A question about memory management and garbage collection
by Nitralime 10 May '11

10 May '11

Hi folks! I have the follwoing situation: A foreign function call returns a pointer to a "table" object. This is an opaque object that can only be manipulated by the APIs provided by the foreign library. To avoid memory leaks the "table" objects should by destroyed by a call to "destroy_table" function if they are not used anymore. I have wrapped the "table" object and its corresponding API functions in a CLOS object with appropriate methods. Instances of this CLOS object will be returned by function calls on the Lisp side. The CLOS instance contains a reference to a C "table" object (allocated on C-heap by foreign library). If a caller in a Lisp program ignores the returned "table" object, it should be garbage collected as expected. My questions are now: 1) Will it be really garbage collected? 2) If the answer is in affirmative, is it garbage collected correctly (no potential memory leaks)? Please note that the C API offers as mentioned above its own dedicated function for that purpose. What would be a correct solution to avoid memory leaks in this situation? Using a finalizer seems to be a possible way to go. But I'm not sure how this can be done by just using the finalizer parameters "object" and "function" where "function" can't reliablely access "object" (cf. documentation of finalizer in "trivial-garbage" package)!! Any help and feedback is very much appreciated! Regards Nik

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[cffi-devel] test failures with acl/windows
by Anton Vodonosov 21 Apr '11

21 Apr '11

Hello. For your information. I've just run the cffi-0.10.6 tests on Allegro 8.2 express edition on Windows. There are failures. I have impression that these failures make CFFI non working even in quite simple and straightforward foreign library interactions from ACL/Windows (I experimented a little in this direction). The full test output is attached. Best regards, - Anton

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